Should I turn off a leaking water heater?
Short answer
Yes. Close the cold water inlet valve at the top of the unit and turn off its power at the breaker or set the gas valve to off. That stops the water supply feeding the leak and prevents the unit from heating improperly.
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Shutdown sequence
- Electric unit: switch off the dedicated breaker. Gas unit: turn the control knob to OFF.
- Close the cold water inlet valve on top of the heater.
- If there's no dedicated inlet valve, close the home's main water supply instead.
- Leave draining or dismantling the unit to the professional unless flooding is imminent.
Why the order matters
Power or gas should be shut off before or alongside the water, not after — a gas or electric water heater that keeps heating with a falling water level can be damaged or, for gas units, create a more serious hazard than the leak itself. That's why shutting off energy to the unit is not an optional second step.
When to leave the property instead
If you smell gas, do not operate any switches, including light switches near the unit. Leave the property immediately and call the gas utility or 911 from outside rather than attempting the shutdown yourself.
Common mistakes
- Shutting off only the water and leaving an electric unit powered, risking the heating element burning out dry
- Trying to drain the tank yourself while it's still hot, risking scald injury
- Flipping switches near a suspected gas leak instead of leaving the area first
Related questions
Can I keep using cold water?
Usually yes, as long as you closed only the heater's inlet valve rather than the main supply.
How long can a water heater sit shut off before it's a problem?
There's no strict time limit for simply having it off — the concern is only if it's powered while water is not flowing normally, so shutting off both together and leaving it off is safe until a technician arrives.
Is it safe to drain the tank myself once it's shut off?
Only if the water has cooled and you're comfortable connecting a hose to the drain valve; otherwise, leaving it to a technician avoids a scald risk from residual hot water.
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